Founders have more things in their heads, and so much more to worry about. They are constantly worried about uncertainty, about raising money and running out of money, about their employees; their minds are always "on."

Furthermore, founders are constantly bombarded by communications from the rest of the company. It is not uncommon for many founders to go to sleep and wake up with their phones, which impacts their quality of sleep.

In fact, founders are under such high pressure, they feel guilty for sleeping too much. They almost never sleep for the full 8 hours, very likely more like 5-6 hours at most.